Explainer: The world is on fire – and here’s why

Explainer: The world is on fire – and here’s why

The Sierra Hotshots, from the Sierra National Forest, are responding on the front lines of the Ferguson Fire in Yosemite in this US Forest Service photo from California Photo: USDA/US Forest Service

Kinked, buckled, stuck or stalled. It doesn’t matter how you describe it, the ribbon of wind that circles the Earth is doing strange things.

The calamity list includes wildfires across Scandinavia, Greece and California, record heat in Texas, Japan and Africa and flooding rain along the US east coast that could last another week.

“We are seeing some extreme jet stream behaviour, where the jet stream is contorting into these extreme loops, both sharply towards the poles with ridges of high pressure and dips to the equator with troughs of low pressure,’’ said Jeff Masters, co-founder of Weather Underground in Ann Arbor, Michigan. “The extreme configuration is getting stuck in place which means places are getting long periods of extreme weather.’’

Globally, at least 170 people have died in fires, floods and heat on three continents. Electricity markets around the world – and the coal and natural gas that generate the power – have spiked as days of high temperatures through Asia, North America and Europe continue to mount and weary residents turn to air conditioning.

Temperature records were shattered in Japan when readings reached 41C, Waco, Texas, hit an all-time high of 45.5C and Finnish Lapland touched a new mark.

The situation in Scandinavia has been “pretty mind boggling,’’ with the Baltic Sea water rising 15 degrees above average and Lapland north of the Arctic Circle reaching into the 30s, Mr Masters said. “That is really eye-catching sort of heat.’’

Earlier in July, Ouargla, Algeria, hit 51.2C, the highest temperature recorded in Africa, said Kevin Trenberth, senior scientist at the National Centre for Atmospheric Research in Boulder, Colorado.

“In very arid conditions, those sort of things are possible and we are seeing more of them in different places around the world,’’ Mr Trenberth said.

Science will need time to study if this extra-hot summer is because of climate change or bad luck for those baking, soaking and choking, but this is what global warming would look like. The exact cause of why the blocking in the atmosphere got going this July might require a bit of study too, said Greg Carbin, branch chief at the US Weather Prediction Centre in College Park, Maryland.

“Everything is backed up,’’ Mr Carbin said. “And it is global.’’

High on Mr Carbin’s list of potential suspects, but not the only possible perpetrator, is a large high-pressure system lazily spinning clockwise in the western Atlantic, dominating the basin, and leaving weather patterns backed up like cars stuck in rush-hour traffic. On top of that, there is a trough over the Bering Sea, a deep area of low pressure helping keep the US south-west hot.

“It is really a chicken-and-egg thing,’’ he said. “It is hard in the atmosphere to know what came first because everything is so interconnected.’’

Climate scientists say they have high confidence human-driven warming is a part of the heatwaves, because the composition of the atmosphere has changed so dramatically in the last generation or two.

“It is important to know that any heatwave has both natural and now, human causes,” said Michael Wehner, a senior staff scientist at Lawrence Berkeley National Laboratory in the US. “So in plain language, climate change simply makes these heatwaves hotter than they would have been otherwise.”

What this means is if it is hot where you are it will probably stay that way. If it is raining, get used to it.